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authorAvi Kivity <avi@redhat.com>2010-05-06 11:45:45 +0300
committerH. Peter Anvin <hpa@zytor.com>2010-05-10 10:39:33 -0700
commitc9ad488289144ae5ef53b012e15895ef1f5e4bb6 (patch)
tree06c29cda09e204d3b0b5b3d9a2a97bda0b4e340d /arch/x86/kernel/xsave.c
parent250825008f1f94887bc039e9227a8adfb5ba366e (diff)
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x86: Eliminate TS_XSAVE
The fpu code currently uses current->thread_info->status & TS_XSAVE as a way to distinguish between XSAVE capable processors and older processors. The decision is not really task specific; instead we use the task status to avoid a global memory reference - the value should be the same across all threads. Eliminate this tie-in into the task structure by using an alternative instruction keyed off the XSAVE cpu feature; this results in shorter and faster code, without introducing a global memory reference. [ hpa: in the future, this probably should use an asm jmp ] Signed-off-by: Avi Kivity <avi@redhat.com> Acked-by: Suresh Siddha <suresh.b.siddha@intel.com> LKML-Reference: <1273135546-29690-2-git-send-email-avi@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/kernel/xsave.c')
-rw-r--r--arch/x86/kernel/xsave.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index 782c3a362ec6..c1b0a11033a2 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -99,7 +99,7 @@ int save_i387_xstate(void __user *buf)
if (err)
return err;
- if (task_thread_info(tsk)->status & TS_XSAVE)
+ if (use_xsave())
err = xsave_user(buf);
else
err = fxsave_user(buf);
@@ -116,7 +116,7 @@ int save_i387_xstate(void __user *buf)
clear_used_math(); /* trigger finit */
- if (task_thread_info(tsk)->status & TS_XSAVE) {
+ if (use_xsave()) {
struct _fpstate __user *fx = buf;
struct _xstate __user *x = buf;
u64 xstate_bv;
@@ -225,7 +225,7 @@ int restore_i387_xstate(void __user *buf)
clts();
task_thread_info(current)->status |= TS_USEDFPU;
}
- if (task_thread_info(tsk)->status & TS_XSAVE)
+ if (use_xsave())
err = restore_user_xstate(buf);
else
err = fxrstor_checking((__force struct i387_fxsave_struct *)